Internal combustion engines are generally known. The type of internal combustion engine most commonly used is an internal combustion engine having at least one piston disposed within a cylinder and connected to a crank shaft through the use of a connecting rod. The piston moves from the top of the cylinder to the bottom of the cylinder during operation, this is also referred to as stroke length. Air and fuel that is injected into the cylinder gets compressed as the piston moves toward the top of the cylinder. Once the air and fuel is compressed, it is combusted, forcing the piston to move downward in the cylinder. Air is repeatedly taken into the cylinder, compressed and combusted as the piston moves in the cylinder in a cyclical manner.
The motion of the piston moving in the cylinder is translated to the crank shaft through the connecting rod which translates the linear motion of the piston to rotational motion. The connecting rod has a bearing which is offset from the center of the crank shaft bearing and connected to the connecting rod. As the distance from the bearing to the center of the crank shaft is increased, the stroke length of the piston increases, and the ability to generate an increased amount of torque is increased as well. However, an increased stroke length also increases the amount of compression of the air inside the cylinder. One of the draw backs to an internal combustion engine is that increasing the compression of the air inside the cylinder can cause the air and fuel to combust prematurely. Therefore, in a conventional gasoline internal combustion engine, the stroke length, and hence the maximum torque which can be generated, is limited.
Also, the angle of the connecting rod also changes as the piston moves in the cylinder and the crankshaft rotates. The crank shaft is typically heavy in order to deal with the reciprocating motion of the piston in the cylinder. A great deal of heat and mechanical energy is wasted during this transfer of motion of the piston. The piston also has to stop at a “top dead center” position (the point at which the piston has moved to the top of the cylinder) during the combustion stroke. This allows valuable heat and energy that can be used to provide mechanical energy to escape. Approximately one third of the heat energy from combustion is lost through the cooling system and another third is lost through the exhaust system. This leaves one third of the heat energy from combustion to be used for mechanical energy.
The piston slides in the cylinder and relies on oil to minimize friction. In one portion of the stroke of the piston, the angle of the connecting rod is positioned such that the friction level on one side of the piston increases greatly. If the engine does not have an adequate cooling system, and oil lubrication, the piston would seize inside the cylinder under load. An oil pump is needed to generate significant pressure to keep the bearing sliding on a film of oil, or else the bearings will seize. This friction can also produce inconsistencies in power and reduce the efficiency of the engine. Other points of friction that are located in the valve train also inhibit efficiency as well.
Another type of engine is commonly referred to as a “rotary engine.” This type of engine includes a rotor disposed within a housing, with the rotor mounted on a large circular lobe on an output shaft. The lobe is offset from the center of the output shaft, providing the leverage, and therefore torque necessary for operation. The rotor is typically three-sided, and creates three chambers inside the housing, one chamber for each side of the rotor. Each chamber changes size as the rotor rotates in the housing. As the rotor rotates, each chamber receives air from an intake port, and the air is then compressed in a similar manner to that of an internal combustion engine having pistons. The rotor will continue to rotate, and the air will be combusted, and forced out of an exhaust port. To help keep the chambers separate from one another, seals are used between the rotor and the housing to keep the air and fuel in each of the chambers from mixing.
However, these seals not only rotate in a circular manner with the rotor, but also rotate in an epitrochoidal manner, causing excessive wear in the seals. Also, typical rotary engines do not burn all of the fuel in the chamber during the combustion process due to the poor surface to volume ratio, which leads to reduced fuel economy and higher emissions.
Accordingly, there exists a need for an improved type of internal combustion engine which does not have the disadvantages of an internal combustion engine having pistons, such as poor utilization of combustion energy as mechanical energy, high friction, and being limited by the stroke length of the pistons; as well as not having the disadvantages of a rotary engine, such as poor sealing characteristics, poor fuel economy, and lower torque due to limited leverage at the output shaft.